Java example source code file (BeanUtils.java)

This example Java source code file (BeanUtils.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

bean, beandescriptor, beanutils, error, eventsetdescriptor, indexedpropertydescriptor, introspectionexception, javabean, propertydescriptor, string

The BeanUtils.java Java example source code

/*
 * Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.beans.BeanDescriptor;
import java.beans.EventSetDescriptor;
import java.beans.IndexedPropertyDescriptor;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.MethodDescriptor;
import java.beans.PropertyDescriptor;

/**
 * This class contains utilities useful for JavaBeans regression testing.
 */
public final class BeanUtils {
    /**
     * Disables instantiation.
     */
    private BeanUtils() {
    }

    /**
     * Returns a bean descriptor for specified class.
     *
     * @param type  the class to introspect
     * @return a bean descriptor
     */
    public static BeanDescriptor getBeanDescriptor(Class type) {
        try {
            return Introspector.getBeanInfo(type).getBeanDescriptor();
        } catch (IntrospectionException exception) {
            throw new Error("unexpected exception", exception);
        }
    }

    /**
     * Returns an array of property descriptors for specified class.
     *
     * @param type  the class to introspect
     * @return an array of property descriptors
     */
    public static PropertyDescriptor[] getPropertyDescriptors(Class type) {
        try {
            return Introspector.getBeanInfo(type).getPropertyDescriptors();
        } catch (IntrospectionException exception) {
            throw new Error("unexpected exception", exception);
        }
    }

    /**
     * Returns an array of event set descriptors for specified class.
     *
     * @param type  the class to introspect
     * @return an array of event set descriptors
     */
    public static EventSetDescriptor[] getEventSetDescriptors(Class type) {
        try {
            return Introspector.getBeanInfo(type).getEventSetDescriptors();
        } catch (IntrospectionException exception) {
            throw new Error("unexpected exception", exception);
        }
    }

    /**
     * Finds an event set descriptor for the class
     * that matches the event set name.
     *
     * @param type  the class to introspect
     * @param name  the name of the event set to search
     * @return the {@code EventSetDescriptor} or {@code null}
     */
    public static EventSetDescriptor findEventSetDescriptor(Class type, String name) {
        EventSetDescriptor[] esds = getEventSetDescriptors(type);
        for (EventSetDescriptor esd : esds) {
            if (esd.getName().equals(name)) {
                return esd;
            }
        }
        return null;
    }

    /**
     * Finds a property descriptor for the class
     * that matches the property name.
     *
     * @param type the class to introspect
     * @param name the name of the property to search
     * @return the {@code PropertyDescriptor}, {@code IndexedPropertyDescriptor} or {@code null}
     */
    public static PropertyDescriptor findPropertyDescriptor(Class type, String name) {
        PropertyDescriptor[] pds = getPropertyDescriptors(type);
        for (PropertyDescriptor pd : pds) {
            if (pd.getName().equals(name)) {
                return pd;
            }
        }
        return null;
    }

    /**
     * Returns a event set descriptor for the class
     * that matches the property name.
     *
     * @param type the class to introspect
     * @param name the name of the event set to search
     * @return the {@code EventSetDescriptor}
     */
    public static EventSetDescriptor getEventSetDescriptor(Class type, String name) {
        EventSetDescriptor esd = findEventSetDescriptor(type, name);
        if (esd != null) {
            return esd;
        }
        throw new Error("could not find event set '" + name + "' in " + type);
    }

    /**
     * Returns a property descriptor for the class
     * that matches the property name.
     *
     * @param type the class to introspect
     * @param name the name of the property to search
     * @return the {@code PropertyDescriptor}
     */
    public static PropertyDescriptor getPropertyDescriptor(Class type, String name) {
        PropertyDescriptor pd = findPropertyDescriptor(type, name);
        if (pd != null) {
            return pd;
        }
        throw new Error("could not find property '" + name + "' in " + type);
    }

    /**
     * Returns an indexed property descriptor for the class
     * that matches the property name.
     *
     * @param type  the class to introspect
     * @param name  the name of the property to search
     * @return the {@code IndexedPropertyDescriptor}
     */
    public static IndexedPropertyDescriptor getIndexedPropertyDescriptor(Class type, String name) {
        PropertyDescriptor pd = findPropertyDescriptor(type, name);
        if (pd instanceof IndexedPropertyDescriptor) {
            return (IndexedPropertyDescriptor) pd;
        }
        reportPropertyDescriptor(pd);
        throw new Error("could not find indexed property '" + name + "' in " + type);
    }

    /**
     * Reports all the interesting information in an Indexed/PropertyDescrptor.
     */
    public static void reportPropertyDescriptor(PropertyDescriptor pd) {
        System.out.println("property name:  " + pd.getName());
        System.out.println("         type:  " + pd.getPropertyType());
        System.out.println("         read:  " + pd.getReadMethod());
        System.out.println("         write: " + pd.getWriteMethod());
        if (pd instanceof IndexedPropertyDescriptor) {
            IndexedPropertyDescriptor ipd = (IndexedPropertyDescriptor) pd;
            System.out.println(" indexed type: " + ipd.getIndexedPropertyType());
            System.out.println(" indexed read: " + ipd.getIndexedReadMethod());
            System.out.println(" indexed write: " + ipd.getIndexedWriteMethod());
        }
    }

    /**
     * Reports all the interesting information in an EventSetDescriptor
     */
    public static void reportEventSetDescriptor(EventSetDescriptor esd) {
        System.out.println("event set name:   " + esd.getName());
        System.out.println(" listener type:   " + esd.getListenerType());
        System.out.println("   method get:    " + esd.getGetListenerMethod());
        System.out.println("   method add:    " + esd.getAddListenerMethod());
        System.out.println("   method remove: " + esd.getRemoveListenerMethod());
    }

    /**
     * Reports all the interesting information in a MethodDescriptor
     */
    public static void reportMethodDescriptor(MethodDescriptor md) {
        System.out.println("method name: " + md.getName());
        System.out.println("     method: " + md.getMethod());
    }
}